fixed missing Idle events

[wxWidgets.git] / src / msw / toplevel.cpp

diff --git a/src/msw/toplevel.cpp b/src/msw/toplevel.cpp
index 83c019347d4182b5ebd82376f576622e082bcb02..7d0164a3c0ccd1b5b0ab795ad01c1a6949c667d7 100644 (file)
--- a/src/msw/toplevel.cpp
+++ b/src/msw/toplevel.cpp
@@ -6,7 +6,7 @@
 // Created:     24.09.01
 // RCS-ID:      $Id$
 // Copyright:   (c) 2001 SciTech Software, Inc. (www.scitechsoft.com)
 // Created:     24.09.01
 // RCS-ID:      $Id$
 // Copyright:   (c) 2001 SciTech Software, Inc. (www.scitechsoft.com)

-// License:     wxWindows license
+// License:     wxWindows licence

 ///////////////////////////////////////////////////////////////////////////////
 
 // ============================================================================
 ///////////////////////////////////////////////////////////////////////////////
 
 // ============================================================================


@@ -35,11 +35,14 @@
     #include "wx/log.h"
     #include "wx/intl.h"
     #include "wx/frame.h"
     #include "wx/log.h"
     #include "wx/intl.h"
     #include "wx/frame.h"

+    #include "wx/containr.h"        // wxSetFocusToChild()

 #endif //WX_PRECOMP
 
 #endif //WX_PRECOMP
 

+#include "wx/module.h"
+

 #include "wx/msw/private.h"
 
 #include "wx/msw/private.h"
 

-#include "wx/popupwin.h"
+#include "wx/display.h"

 
 #ifndef ICON_BIG
     #define ICON_BIG 1
 
 #ifndef ICON_BIG
     #define ICON_BIG 1


@@ -60,6 +63,11 @@ static inline bool IsZoomed(HWND WXUNUSED(hwnd)) { return FALSE; }
 
 #endif // __WXMICROWIN__
 
 
 #endif // __WXMICROWIN__
 

+// NB: wxDlgProc must be defined here and not in dialog.cpp because the latter
+//     is not included by wxUniv build which does need wxDlgProc
+LONG APIENTRY _EXPORT
+wxDlgProc(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam);
+

 // ----------------------------------------------------------------------------
 // globals
 // ----------------------------------------------------------------------------
 // ----------------------------------------------------------------------------
 // globals
 // ----------------------------------------------------------------------------


@@ -70,31 +78,40 @@ wxWindowList wxModelessWindows;
 // the name of the default wxWindows class
 extern const wxChar *wxCanvasClassName;
 
 // the name of the default wxWindows class
 extern const wxChar *wxCanvasClassName;
 

-// ============================================================================
-// wxTopLevelWindowMSW implementation
-// ============================================================================
-

 // ----------------------------------------------------------------------------
 // ----------------------------------------------------------------------------

-// wxDialog helpers
+// wxTLWHiddenParentModule: used to manage the hidden parent window (we need a
+// module to ensure that the window is always deleted)

 // ----------------------------------------------------------------------------
 
 // ----------------------------------------------------------------------------
 

-// Dialog window proc
-LONG APIENTRY _EXPORT
-wxDlgProc(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
+class wxTLWHiddenParentModule : public wxModule

 {
 {

-    switch ( message )
-    {
-        case WM_INITDIALOG:
-            // for this message, returning TRUE tells system to set focus to the
-            // first control in the dialog box
-            return TRUE;
+public:
+    // module init/finalize
+    virtual bool OnInit();
+    virtual void OnExit();

 
 

-        default:
-            // for all the other ones, FALSE means that we didn't process the
-            // message
-            return FALSE;
-    }
-}
+    // get the hidden window (creates on demand)
+    static HWND GetHWND();
+
+private:
+    // the HWND of the hidden parent
+    static HWND ms_hwnd;
+
+    // the class used to create it
+    static const wxChar *ms_className;
+
+    DECLARE_DYNAMIC_CLASS(wxTLWHiddenParentModule)
+};
+
+IMPLEMENT_DYNAMIC_CLASS(wxTLWHiddenParentModule, wxModule)
+
+// ============================================================================
+// wxTopLevelWindowMSW implementation
+// ============================================================================
+
+BEGIN_EVENT_TABLE(wxTopLevelWindowMSW, wxTopLevelWindowBase)
+    EVT_ACTIVATE(wxTopLevelWindowMSW::OnActivate)
+END_EVENT_TABLE()

 
 // ----------------------------------------------------------------------------
 // wxTopLevelWindowMSW creation
 
 // ----------------------------------------------------------------------------
 // wxTopLevelWindowMSW creation


@@ -113,6 +130,8 @@ void wxTopLevelWindowMSW::Init()
     m_fsOldWindowStyle = 0;
     m_fsIsMaximized = FALSE;
     m_fsIsShowing = FALSE;
     m_fsOldWindowStyle = 0;
     m_fsIsMaximized = FALSE;
     m_fsIsShowing = FALSE;

+
+    m_winLastFocused = (wxWindow *)NULL;

 }
 
 WXDWORD wxTopLevelWindowMSW::MSWGetStyle(long style, WXDWORD *exflags) const
 }
 
 WXDWORD wxTopLevelWindowMSW::MSWGetStyle(long style, WXDWORD *exflags) const


@@ -175,14 +194,30 @@ WXDWORD wxTopLevelWindowMSW::MSWGetStyle(long style, WXDWORD *exflags) const
 #if !defined(__WIN16__) && !defined(__SC__)
         if ( !(GetExtraStyle() & wxTOPLEVEL_EX_DIALOG) )
         {
 #if !defined(__WIN16__) && !defined(__SC__)
         if ( !(GetExtraStyle() & wxTOPLEVEL_EX_DIALOG) )
         {

-            // make all frames appear in the win9x shell taskbar unless
-            // wxFRAME_TOOL_WINDOW or wxFRAME_NO_TASKBAR is given - without
-            // giving them WS_EX_APPWINDOW style, the child (i.e. owned) frames
-            // wouldn't appear in it
-            if ( (style & wxFRAME_TOOL_WINDOW) || (style & wxFRAME_NO_TASKBAR) )
+            if ( style & wxFRAME_TOOL_WINDOW )
+            {
+                // create the palette-like window

                 *exflags |= WS_EX_TOOLWINDOW;
                 *exflags |= WS_EX_TOOLWINDOW;

-            else if ( !(style & wxFRAME_NO_TASKBAR) )
+            }
+
+            // We have to solve 2 different problems here:
+            //
+            // 1. frames with wxFRAME_NO_TASKBAR flag shouldn't appear in the
+            //    taskbar even if they don't have a parent
+            //
+            // 2. frames without this style should appear in the taskbar even
+            //    if they're owned (Windows only puts non owned windows into
+            //    the taskbar normally)
+            //
+            // The second one is solved here by using WS_EX_APPWINDOW flag, the
+            // first one is dealt with in our MSWGetParent() method
+            // implementation
+            if ( !(style & wxFRAME_NO_TASKBAR) && GetParent() )
+            {
+                // need to force the frame to appear in the taskbar

                 *exflags |= WS_EX_APPWINDOW;
                 *exflags |= WS_EX_APPWINDOW;

+            }
+            //else: nothing to do [here]

         }
 #endif // !Win16
 
         }
 #endif // !Win16
 


@@ -198,6 +233,40 @@ WXDWORD wxTopLevelWindowMSW::MSWGetStyle(long style, WXDWORD *exflags) const
     return msflags;
 }
 
     return msflags;
 }
 

+WXHWND wxTopLevelWindowMSW::MSWGetParent() const
+{
+    // for the frames without wxFRAME_FLOAT_ON_PARENT style we should use NULL
+    // parent HWND or it would be always on top of its parent which is not what
+    // we usually want (in fact, we only want it for frames with the
+    // wxFRAME_FLOAT_ON_PARENT flag)
+    HWND hwndParent = NULL;
+    if ( HasFlag(wxFRAME_FLOAT_ON_PARENT) )
+    {
+        const wxWindow *parent = GetParent();
+
+        if ( !parent )
+        {
+            // this flag doesn't make sense then and will be ignored
+            wxFAIL_MSG( _T("wxFRAME_FLOAT_ON_PARENT but no parent?") );
+        }
+        else
+        {
+            hwndParent = GetHwndOf(parent);
+        }
+    }
+    //else: don't float on parent, must not be owned
+
+    // now deal with the 2nd taskbar-related problem (see comments above in
+    // MSWGetStyle())
+    if ( HasFlag(wxFRAME_NO_TASKBAR) && !hwndParent )
+    {
+        // use hidden parent
+        hwndParent = wxTLWHiddenParentModule::GetHWND();
+    }
+
+    return (WXHWND)hwndParent;
+}
+

 bool wxTopLevelWindowMSW::CreateDialog(const void *dlgTemplate,
                                        const wxString& title,
                                        const wxPoint& pos,
 bool wxTopLevelWindowMSW::CreateDialog(const void *dlgTemplate,
                                        const wxString& title,
                                        const wxPoint& pos,


@@ -241,9 +310,9 @@ bool wxTopLevelWindowMSW::CreateDialog(const void *dlgTemplate,
 
     if ( !m_hWnd )
     {
 
     if ( !m_hWnd )
     {

-        wxFAIL_MSG(_("Failed to create dialog. Incorrect DLGTEMPLATE?"));
+        wxFAIL_MSG(wxT("Failed to create dialog. Incorrect DLGTEMPLATE?"));

 
 

-        wxLogSysError(_("Can't create dialog using memory template"));
+        wxLogSysError(wxT("Can't create dialog using memory template"));

 
         return FALSE;
     }
 
         return FALSE;
     }


@@ -345,6 +414,8 @@ bool wxTopLevelWindowMSW::Create(wxWindow *parent,
                                  long style,
                                  const wxString& name)
 {
                                  long style,
                                  const wxString& name)
 {

+    bool ret = false;
+

     // init our fields
     Init();
 
     // init our fields
     Init();
 


@@ -389,32 +460,37 @@ bool wxTopLevelWindowMSW::Create(wxWindow *parent,
         if ( style & (wxRESIZE_BORDER | wxCAPTION) )
             dlgTemplate->style |= DS_MODALFRAME;
 
         if ( style & (wxRESIZE_BORDER | wxCAPTION) )
             dlgTemplate->style |= DS_MODALFRAME;
 

-        bool ret = CreateDialog(dlgTemplate, title, pos, size);
+        ret = CreateDialog(dlgTemplate, title, pos, size);

         free(dlgTemplate);
         free(dlgTemplate);

-
-        return ret;

     }
     else // !dialog
     {
     }
     else // !dialog
     {

-        return CreateFrame(title, pos, size);
+        ret = CreateFrame(title, pos, size);

     }
     }

+
+    if ( ret && !(GetWindowStyleFlag() & wxCLOSE_BOX) )
+    {
+        EnableCloseButton(false);
+    }
+
+    return ret;

 }
 
 wxTopLevelWindowMSW::~wxTopLevelWindowMSW()
 {
 }
 
 wxTopLevelWindowMSW::~wxTopLevelWindowMSW()
 {

-    wxTopLevelWindows.DeleteObject(this);
-

     if ( wxModelessWindows.Find(this) )
         wxModelessWindows.DeleteObject(this);
 
     if ( wxModelessWindows.Find(this) )
         wxModelessWindows.DeleteObject(this);
 

-    // If this is the last top-level window, exit.
-    if ( wxTheApp && (wxTopLevelWindows.Number() == 0) )
+    // after destroying an owned window, Windows activates the next top level
+    // window in Z order but it may be different from our owner (to reproduce
+    // this simply Alt-TAB to another application and back before closing the
+    // owned frame) whereas we always want to yield activation to our parent
+    if ( HasFlag(wxFRAME_FLOAT_ON_PARENT) )

     {
     {

-        wxTheApp->SetTopWindow(NULL);
-
-        if ( wxTheApp->GetExitOnFrameDelete() )
+        wxWindow *parent = GetParent();
+        if ( parent )

         {
         {

-            ::PostQuitMessage(0);
+            ::BringWindowToTop(GetHwndOf(parent));

         }
     }
 }
         }
     }
 }


@@ -448,7 +524,10 @@ bool wxTopLevelWindowMSW::Show(bool show)
         }
         else // just show
         {
         }
         else // just show
         {

-            nShowCmd = SW_SHOW;
+           if ( GetWindowStyle() & wxFRAME_TOOL_WINDOW )
+               nShowCmd = SW_SHOWNA;
+           else
+               nShowCmd = SW_SHOW;

         }
     }
     else // hide
         }
     }
     else // hide


@@ -495,7 +574,7 @@ void wxTopLevelWindowMSW::Maximize(bool maximize)
     {
         // we can't maximize the hidden frame because it shows it as well, so
         // just remember that we should do it later in this case
     {
         // we can't maximize the hidden frame because it shows it as well, so
         // just remember that we should do it later in this case

-        m_maximizeOnShow = TRUE;
+        m_maximizeOnShow = maximize;

     }
 }
 
     }
 }
 


@@ -528,18 +607,22 @@ void wxTopLevelWindowMSW::Restore()
 
 bool wxTopLevelWindowMSW::ShowFullScreen(bool show, long style)
 {
 
 bool wxTopLevelWindowMSW::ShowFullScreen(bool show, long style)
 {

-    if (show)
+    if ( show == IsFullScreen() )

     {
     {

-        if (IsFullScreen())
-            return FALSE;
+        // nothing to do
+        return TRUE;
+    }

 
 

-        m_fsIsShowing = TRUE;
+    m_fsIsShowing = show;
+
+    if ( show )
+    {

         m_fsStyle = style;
 
         // zap the frame borders
 
         // save the 'normal' window style
         m_fsStyle = style;
 
         // zap the frame borders
 
         // save the 'normal' window style

-        m_fsOldWindowStyle = GetWindowLong((HWND)GetHWND(), GWL_STYLE);
+        m_fsOldWindowStyle = GetWindowLong(GetHwnd(), GWL_STYLE);

 
         // save the old position, width & height, maximize state
         m_fsOldSize = GetRect();
 
         // save the old position, width & height, maximize state
         m_fsOldSize = GetRect();


@@ -552,44 +635,64 @@ bool wxTopLevelWindowMSW::ShowFullScreen(bool show, long style)
         if (style & wxFULLSCREEN_NOBORDER)
             offFlags |= WS_BORDER | WS_THICKFRAME;
         if (style & wxFULLSCREEN_NOCAPTION)
         if (style & wxFULLSCREEN_NOBORDER)
             offFlags |= WS_BORDER | WS_THICKFRAME;
         if (style & wxFULLSCREEN_NOCAPTION)

-            offFlags |= (WS_CAPTION | WS_SYSMENU);
+            offFlags |= WS_CAPTION | WS_SYSMENU;

 
 

-        newStyle &= (~offFlags);
+        newStyle &= ~offFlags;

 
         // change our window style to be compatible with full-screen mode
 
         // change our window style to be compatible with full-screen mode

-        ::SetWindowLong((HWND)GetHWND(), GWL_STYLE, newStyle);
-
-        // resize to the size of the desktop
-        int width, height;
+        ::SetWindowLong(GetHwnd(), GWL_STYLE, newStyle);

 
 

-        RECT rect = wxGetWindowRect(::GetDesktopWindow());
-        width = rect.right - rect.left;
-        height = rect.bottom - rect.top;
+        wxRect rect;
+#if wxUSE_DISPLAY
+        // resize to the size of the display containing us
+        int dpy = wxDisplay::GetFromWindow(this);
+        if ( dpy != wxNOT_FOUND )
+        {
+            rect = wxDisplay(dpy).GetGeometry();
+        }
+        else // fall back to the main desktop
+#else // wxUSE_DISPLAY
+        {
+            // resize to the size of the desktop
+            wxCopyRECTToRect(wxGetWindowRect(::GetDesktopWindow()), rect);
+        }
+#endif // wxUSE_DISPLAY

 
 

-        SetSize(width, height);
+        SetSize(rect);

 
         // now flush the window style cache and actually go full-screen
 
         // now flush the window style cache and actually go full-screen

-        SetWindowPos((HWND)GetHWND(), HWND_TOP, 0, 0, width, height, SWP_FRAMECHANGED);
+        long flags = SWP_FRAMECHANGED;

 
 

-        wxSizeEvent event(wxSize(width, height), GetId());
-        GetEventHandler()->ProcessEvent(event);
+        // showing the frame full screen should also show it if it's still
+        // hidden
+        if ( !IsShown() )
+        {
+            // don't call wxWindow version to avoid flicker from calling
+            // ::ShowWindow() -- we're going to show the window at the correct
+            // location directly below -- but do call the wxWindowBase version
+            // to sync the internal m_isShown flag
+            wxWindowBase::Show();

 
 

-        return TRUE;
-    }
-    else
-    {
-        if (!IsFullScreen())
-            return FALSE;
+            flags |= SWP_SHOWWINDOW;
+        }

 
 

-        m_fsIsShowing = FALSE;
+        SetWindowPos(GetHwnd(), HWND_TOP,
+                     rect.x, rect.y, rect.width, rect.height,
+                     flags);

 
 

+        // finally send an event allowing the window to relayout itself &c
+        wxSizeEvent event(rect.GetSize(), GetId());
+        GetEventHandler()->ProcessEvent(event);
+    }
+    else // stop showing full screen
+    {

         Maximize(m_fsIsMaximized);
         Maximize(m_fsIsMaximized);

-        SetWindowLong((HWND)GetHWND(),GWL_STYLE, m_fsOldWindowStyle);
-        SetWindowPos((HWND)GetHWND(),HWND_TOP,m_fsOldSize.x, m_fsOldSize.y,
+        SetWindowLong(GetHwnd(),GWL_STYLE, m_fsOldWindowStyle);
+        SetWindowPos(GetHwnd(),HWND_TOP,m_fsOldSize.x, m_fsOldSize.y,

             m_fsOldSize.width, m_fsOldSize.height, SWP_FRAMECHANGED);
             m_fsOldSize.width, m_fsOldSize.height, SWP_FRAMECHANGED);

-
-        return TRUE;

     }
     }

+
+    return TRUE;

 }
 
 // ----------------------------------------------------------------------------
 }
 
 // ----------------------------------------------------------------------------


@@ -655,41 +758,199 @@ bool wxTopLevelWindowMSW::EnableCloseButton(bool enable)
     return TRUE;
 }
 
     return TRUE;
 }
 

+bool wxTopLevelWindowMSW::SetShape(const wxRegion& region)
+{
+    // The empty region signifies that the shape should be removed from the
+    // window.
+    if ( region.IsEmpty() )
+    {
+        if (::SetWindowRgn(GetHwnd(), NULL, TRUE) == 0)
+        {
+            wxLogLastError(_T("SetWindowRgn"));
+            return FALSE;
+        }
+        return TRUE;
+    }
+
+    // Windows takes ownership of the region, so
+    // we'll have to make a copy of the region to give to it.
+    DWORD noBytes = ::GetRegionData(GetHrgnOf(region), 0, NULL);
+    RGNDATA *rgnData = (RGNDATA*) new char[noBytes];
+    ::GetRegionData(GetHrgnOf(region), noBytes, rgnData);
+    HRGN hrgn = ::ExtCreateRegion(NULL, noBytes, rgnData);
+    delete[] (char*) rgnData;
+
+    // SetWindowRgn expects the region to be in coordinants
+    // relative to the window, not the client area.  Figure
+    // out the offset, if any.
+    RECT rect;
+    DWORD dwStyle =   ::GetWindowLong(GetHwnd(), GWL_STYLE);
+    DWORD dwExStyle = ::GetWindowLong(GetHwnd(), GWL_EXSTYLE);
+    ::GetClientRect(GetHwnd(), &rect);
+    ::AdjustWindowRectEx(&rect, dwStyle, FALSE, dwExStyle);
+    ::OffsetRgn(hrgn, -rect.left, -rect.top);
+
+    // Now call the shape API with the new region.
+    if (::SetWindowRgn(GetHwnd(), hrgn, TRUE) == 0)
+    {
+        wxLogLastError(_T("SetWindowRgn"));
+        return FALSE;
+    }
+    return TRUE;
+}
+

 // ----------------------------------------------------------------------------
 // ----------------------------------------------------------------------------

-// wxTopLevelWindowMSW message processing
+// wxTopLevelWindow event handling

 // ----------------------------------------------------------------------------
 
 // ----------------------------------------------------------------------------
 

-long wxTopLevelWindowMSW::HandleNcActivate(bool activate)
+// Default activation behaviour - set the focus for the first child
+// subwindow found.
+void wxTopLevelWindowMSW::OnActivate(wxActivateEvent& event)

 {
 {

-#if wxUSE_POPUPWIN
-    /*
-       Normally, when another top level (whether it is overlapped or popup)
-       window is shown, it is activated and the parent window (i.e. we) loses
-       the activation. This, however, looks very ugly when the child window is
-       a [custom] combobox which we implement using a popup window as surely
-       opening a combobox shouldn't result in deactivating the parent window.
-
-       So we don't redraw the title bar in this case, even if we still return
-       TRUE to let the change of activation to take place as otherwise the
-       controls inside the popup window wouldn't work properly.
-     */
-    if ( !activate && wxPopupWindow::FindPopupFor(this) )
+    if ( event.GetActive() )

     {
     {

-        return TRUE;
+        // restore focus to the child which was last focused
+        wxLogTrace(_T("focus"), _T("wxTLW %08x activated."), (int) m_hWnd);
+
+        wxWindow *parent = m_winLastFocused ? m_winLastFocused->GetParent()
+                                            : NULL;
+        if ( !parent )
+        {
+            parent = this;
+        }
+
+        wxSetFocusToChild(parent, &m_winLastFocused);

     }
     }

-#endif // wxUSE_POPUPWIN
+    else // deactivating
+    {
+        // remember the last focused child if it is our child
+        m_winLastFocused = FindFocus();

 
 

-    return FALSE;
+        if ( m_winLastFocused )
+        {
+            // let it know that it doesn't have focus any more
+            m_winLastFocused->HandleKillFocus((WXHWND)NULL);
+        }
+
+        // so we NULL it out if it's a child from some other frame
+        wxWindow *win = m_winLastFocused;
+        while ( win )
+        {
+            if ( win->IsTopLevel() )
+            {
+                if ( win != this )
+                {
+                    m_winLastFocused = NULL;
+                }
+
+                break;
+            }
+
+            win = win->GetParent();
+        }
+
+        wxLogTrace(_T("focus"),
+                   _T("wxTLW %08x deactivated, last focused: %08x."),
+                   (int) m_hWnd,
+                   (int) (m_winLastFocused ? GetHwndOf(m_winLastFocused)
+                                           : NULL));
+
+        event.Skip();
+    }

 }
 
 }
 

-long
-wxTopLevelWindowMSW::MSWWindowProc(WXUINT msg, WXWPARAM wParam, WXLPARAM lParam)
+// the DialogProc for all wxWindows dialogs
+LONG APIENTRY _EXPORT
+wxDlgProc(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)

 {
 {

-    if ( msg == WM_NCACTIVATE && HandleNcActivate(wParam != 0) )
+    switch ( message )

     {
     {

-        // we processed WM_NCACTIVATE ourselves
-        return TRUE;
+        case WM_INITDIALOG:
+            // for this message, returning TRUE tells system to set focus to
+            // the first control in the dialog box, but as we set the focus
+            // ourselves, we return FALSE from here as well, so fall through
+
+        default:
+            // for all the other ones, FALSE means that we didn't process the
+            // message
+            return FALSE;

     }
     }

+}

 
 

-    return wxTopLevelWindowBase::MSWWindowProc(msg, wParam, lParam);
+// ============================================================================
+// wxTLWHiddenParentModule implementation
+// ============================================================================
+
+HWND wxTLWHiddenParentModule::ms_hwnd = NULL;
+
+const wxChar *wxTLWHiddenParentModule::ms_className = NULL;
+
+bool wxTLWHiddenParentModule::OnInit()
+{
+    ms_hwnd = NULL;
+    ms_className = NULL;
+
+    return TRUE;
+}
+
+void wxTLWHiddenParentModule::OnExit()
+{
+    if ( ms_hwnd )
+    {
+        if ( !::DestroyWindow(ms_hwnd) )
+        {
+            wxLogLastError(_T("DestroyWindow(hidden TLW parent)"));
+        }
+
+        ms_hwnd = NULL;
+    }
+
+    if ( ms_className )
+    {
+        if ( !::UnregisterClass(ms_className, wxGetInstance()) )
+        {
+            wxLogLastError(_T("UnregisterClass(\"wxTLWHiddenParent\")"));
+        }
+
+        ms_className = NULL;
+    }

 }
 }

+
+/* static */
+HWND wxTLWHiddenParentModule::GetHWND()
+{
+    if ( !ms_hwnd )
+    {
+        if ( !ms_className )
+        {
+            static const wxChar *HIDDEN_PARENT_CLASS = _T("wxTLWHiddenParent");
+
+            WNDCLASS wndclass;
+            wxZeroMemory(wndclass);
+
+            wndclass.lpfnWndProc   = DefWindowProc;
+            wndclass.hInstance     = wxGetInstance();
+            wndclass.lpszClassName = HIDDEN_PARENT_CLASS;
+
+            if ( !::RegisterClass(&wndclass) )
+            {
+                wxLogLastError(_T("RegisterClass(\"wxTLWHiddenParent\")"));
+            }
+            else
+            {
+                ms_className = HIDDEN_PARENT_CLASS;
+            }
+        }
+
+        ms_hwnd = ::CreateWindow(ms_className, _T(""), 0, 0, 0, 0, 0, NULL,
+                                 (HMENU)NULL, wxGetInstance(), NULL);
+        if ( !ms_hwnd )
+        {
+            wxLogLastError(_T("CreateWindow(hidden TLW parent)"));
+        }
+    }
+
+    return ms_hwnd;
+}
+
+